RIP Banebot RS550

[Jared Russell]

As long as the RS775-18 continues to be available, my reaction to this is a resounding "meh".

[billbo911]

Originally Posted by Jared Russell

As long as the RS775-18 continues to be available, my reaction to this is a resounding "meh".

My thoughts exactly! (RS775-18, not RS775-125. Don't confuse the two!)

Let's look at the specs: (See attachment)

775 has more peak power. 775 has ~60% more stall torque. They have practically identical stall current.

The one additional advantage the 775's have is their ability to absorb and dissipate more heat than the 550s.

On a side by side, the 775 is a better motor in many situations.

[Monochron]

Originally Posted by billbo911

775 has more peak power. 775 has ~60% more stall torque. They have practically identical stall current.

The one additional advantage the 775's have is their ability to absorb and dissipate more heat than the 550s.

Geared to the same speed as the RS 775, the RS 550 has very close to the same stall torque. Max power is the important factor and while, yes, the 775 definitely has it beat, I love how small the 550 is
Maybe not the best factor to base motor choice on. Especially considering heat dissipation. I just love the ability to swap out a BAG or AM motor for a 550 with very little hassle.

[AdamHeard]

Originally Posted by Monochron

Geared to the same speed as the RS 775, the RS 550 has very close to the same stall torque. Max power is the important factor and while, yes, the 775 definitely has it beat, I love how small the 550 is
Maybe not the best factor to base motor choice on. Especially considering heat dissipation. I just love the ability to swap out a BAG or AM motor for a 550 with very little hassle.

I'm pretty certain the 550 specs are not accurate, and it's 20-30% less powerful than claimed.

[sanddrag]

Originally Posted by AdamHeard

I'm pretty certain the 550 specs are not accurate, and it's 20-30% less powerful than claimed.

Agreed.

[billbo911]

Originally Posted by AdamHeard

I'm pretty certain the 550 specs are not accurate, and it's 20-30% less powerful than claimed.

Originally Posted by sanddrag

Agreed.

Got a Dyno we can test with?? If your assertions are correct, that would explain a lot.
Seriously, how many times have you run all the calculations and built a design only to see it's performance not live up the the numbers?
THAT REALLY BITES!

[sanddrag]

Originally Posted by billbo911

Got a Dyno we can test with??

Yes, I do. It's about 6 feet tall and 120 lbs and it lifts totes slower than it should....

[Michael Hill]

Originally Posted by billbo911

Got a Dyno we can test with?? If your assertions are correct, that would explain a lot.
Seriously, how many times have you run all the calculations and built a design only to see it's performance not live up the the numbers?
THAT REALLY BITES!

Did this year...The 550s should have been able to easily handle our elevator system. They held up for most of two regionals, but ended up switching to BAG motors because they spent a little too much time near stall and burned out right before elims.

[AdamHeard]

Originally Posted by billbo911

Got a Dyno we can test with?? If your assertions are correct, that would explain a lot.
Seriously, how many times have you run all the calculations and built a design only to see it's performance not live up the the numbers?
THAT REALLY BITES!

I sort of dyno'd them with our 2012 robot.

In 2012 we only had 4-6 of the Fisher Price motor that was real high power, so we saved them for comp. Ran 550's on the practice bot.

The practice bot performed way worse in terms of spinup time and peak rpm. The 550's had lower ratings than the FP's, but not by enough to explain it. I repeated the test on the same robot with the FPs, 550s, the andymark 9015's and some 550 sized mabuchi motors I bought surplus.

I characterized the flywheel roughly in terms of friction (a polynomial in the form Ax^2 +Bc + C) and all the motors matched with their specs pretty well... except the 550's.

Not the most scientific test as I wasn't measuring torque directly, but I'm reasonably certain the banebots 550's are not as powerful as claimed. Unsure if this was a batch issue, a supplier misleading banebots, banebots mislabeling, etc...

[Jared Russell]

I know of people who have done dyno tests that confirm the RS550 falls well short of its rated torque constant.

[Travis Covington]

Originally Posted by Jared Russell

I know of people who have done dyno tests that confirm the RS550 falls well short of its rated torque constant.

This. The performance of the RS550 never matches its data sheet. We stopped using the RS550 in the middle of 2014 when we had numerous 550s fry in our shooter (not really due to the lacking power). The RS775-18 is a superior motor, with power ratings that are actually accurate. I would encourage teams to look at using them instead.

[AllenGregoryIV]

Just cause this conversation was getting a little crazy. I called up Banebots.

They are actually going to stop selling all of their motors. They were just importing all the motors and reselling them and that wasn't something they wanted to keep doing.

They said Robotshop is going to start carrying them but they don't seem to have 775-18s listed on their website yet.

[Monochron]

Originally Posted by AllenGregoryIV

They are actually going to stop selling all of their motors.
They said Robotshop is going to start carrying them but they don't seem to have 775-18s listed on their website yet.

Great, I was just about to calm down and be happy with the 775-18s.

I'm assuming Banebots was importing them in bulk? And that a private consumer would have trouble getting them in the same way?

[AllenGregoryIV]

Originally Posted by Monochron

Great, I was just about to calm down and be happy with the 775-18s.

I'm assuming Banebots was importing them in bulk? And that a private consumer would have trouble getting them in the same way?

If there isn't a reliable source then FIRST won't put them on the allowed motor list. They trimmed the list of allowed Banebots motors this year in response to Banebots asking them to do it. We used to have the 555, 395, etc. This year only BB775 and BB550 motors were allowed. If there isn't a good source, 775-18v will probably not be allowed next year.

I have a support ticket open with RobotShop to see if they plan to carry the 775-18v I'll post here when they give me an answer.

Hopefully some one comes through and i a reliable importer for these motors (VEXpro or AndyMark would be ideal).

I just got an answer back from RobotShop
"We thank you for your input. We do plan to carry the standard version of the RS-775 DC motor; the specs are slightly different, but the mounting is the same, and it is still a high torque motor. Unfortunately these are produced in high volume and it may be some time before we receive new stock. We will soon also carry new gearmotro systems which incorporate a 775 motor so we invite you to take a look at our New Arrivals section over the coming weeks and check out this new section.

Hope this helps,"

That doesn't look good.

Update
Longer phone call with Banebots just now.

They believe that RobotShop is going to pickup up both the RS550 and RS775-18v and that was discussed with the RobotShop when they agreed to stop importing motors. They also talked to RobotShop about FRC and the use of those to motors in FRC.

Hopefully that means they will both be back and hopefully FRC will continue to allow them as legal motors but who knows what the rules will be for next year.

[Thad House]

I could live with the 550's being gone, But the 775-18's being gone would really hurt a lot of FRC teams. The BAG motor just isn't powerful enough, and CIMs are just too big. The 775-18 was a perfect motor (after 2011's short issues) and it would be really disappointing to lose it.